Thermodynamic Guidelines for the Mechanosynthesis or Solid-State Synthesis of MnFe<sub>2</sub>O<sub>4</sub> at Relatively Low Temperatures
Herein, thermodynamic assessment is proposed to screen suitable precursors for the solid-state synthesis of manganese ferrite, by mechanosynthesis at room temperature or by subsequent calcination at relatively low temperatures, and the main findings are validated by experimental results for the repr...
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2024-01-01
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| Online Access: | https://www.mdpi.com/1996-1944/17/2/299 |
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| author | Isabel Antunes Miguel F. Baptista Andrei V. Kovalevsky Aleksey A. Yaremchenko Jorge R. Frade |
| author_facet | Isabel Antunes Miguel F. Baptista Andrei V. Kovalevsky Aleksey A. Yaremchenko Jorge R. Frade |
| author_sort | Isabel Antunes |
| collection | DOAJ |
| description | Herein, thermodynamic assessment is proposed to screen suitable precursors for the solid-state synthesis of manganese ferrite, by mechanosynthesis at room temperature or by subsequent calcination at relatively low temperatures, and the main findings are validated by experimental results for the representative precursor mixtures MnO + FeO<sub>3</sub>, MnO<sub>2</sub> + Fe<sub>2</sub>O<sub>3</sub>, and MnO<sub>2</sub> +2FeCO<sub>3</sub>. Thermodynamic guidelines are provided for the synthesis of manganese ferrite from (i) oxide and/or metallic precursors; (ii) carbonate + carbonate or carbonate + oxide powder mixtures; (iii) other precursors. It is also shown that synthesis from metallic precursors (Mn + 2Fe) requires a controlled oxygen supply in limited redox conditions, which is hardly achieved by reducing gases H<sub>2</sub>/H<sub>2</sub>O or CO/CO<sub>2</sub>. Oxide mixtures with an overall oxygen balance, such as MnO + Fe<sub>2</sub>O<sub>3</sub>, act as self-redox buffers and offer prospects for mechanosynthesis for a sufficient time (>9 h) at room temperature. On the contrary, the fully oxidised oxide mixture MnO<sub>2</sub> + Fe<sub>2</sub>O<sub>3</sub> requires partial reduction, which prevents synthesis at room temperature and requires subsequent calcination at temperatures above 1100 °C in air or in nominally inert atmospheres above 750 °C. Oxide + carbonate mixtures, such as MnO<sub>2</sub> +2FeCO<sub>3</sub>, also yield suitable oxygen balance by the decomposition of the carbonate precursor and offer prospects for mechanosynthesis at room temperature, and residual fractions of reactants could be converted by firing at relatively low temperatures (≥650 °C). |
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| issn | 1996-1944 |
| language | English |
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| spelling | doaj.art-360ae984a8c4419aa6e11b8441ca399d2024-01-26T17:26:31ZengMDPI AGMaterials1996-19442024-01-0117229910.3390/ma17020299Thermodynamic Guidelines for the Mechanosynthesis or Solid-State Synthesis of MnFe<sub>2</sub>O<sub>4</sub> at Relatively Low TemperaturesIsabel Antunes0Miguel F. Baptista1Andrei V. Kovalevsky2Aleksey A. Yaremchenko3Jorge R. Frade4Department of Materials and Ceramics Engineering, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, PortugalDepartment of Materials and Ceramics Engineering, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, PortugalDepartment of Materials and Ceramics Engineering, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, PortugalDepartment of Materials and Ceramics Engineering, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, PortugalDepartment of Materials and Ceramics Engineering, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, PortugalHerein, thermodynamic assessment is proposed to screen suitable precursors for the solid-state synthesis of manganese ferrite, by mechanosynthesis at room temperature or by subsequent calcination at relatively low temperatures, and the main findings are validated by experimental results for the representative precursor mixtures MnO + FeO<sub>3</sub>, MnO<sub>2</sub> + Fe<sub>2</sub>O<sub>3</sub>, and MnO<sub>2</sub> +2FeCO<sub>3</sub>. Thermodynamic guidelines are provided for the synthesis of manganese ferrite from (i) oxide and/or metallic precursors; (ii) carbonate + carbonate or carbonate + oxide powder mixtures; (iii) other precursors. It is also shown that synthesis from metallic precursors (Mn + 2Fe) requires a controlled oxygen supply in limited redox conditions, which is hardly achieved by reducing gases H<sub>2</sub>/H<sub>2</sub>O or CO/CO<sub>2</sub>. Oxide mixtures with an overall oxygen balance, such as MnO + Fe<sub>2</sub>O<sub>3</sub>, act as self-redox buffers and offer prospects for mechanosynthesis for a sufficient time (>9 h) at room temperature. On the contrary, the fully oxidised oxide mixture MnO<sub>2</sub> + Fe<sub>2</sub>O<sub>3</sub> requires partial reduction, which prevents synthesis at room temperature and requires subsequent calcination at temperatures above 1100 °C in air or in nominally inert atmospheres above 750 °C. Oxide + carbonate mixtures, such as MnO<sub>2</sub> +2FeCO<sub>3</sub>, also yield suitable oxygen balance by the decomposition of the carbonate precursor and offer prospects for mechanosynthesis at room temperature, and residual fractions of reactants could be converted by firing at relatively low temperatures (≥650 °C).https://www.mdpi.com/1996-1944/17/2/299manganese ferritemechanosynthesissolid-state synthesisthermodynamic guidelines |
| spellingShingle | Isabel Antunes Miguel F. Baptista Andrei V. Kovalevsky Aleksey A. Yaremchenko Jorge R. Frade Thermodynamic Guidelines for the Mechanosynthesis or Solid-State Synthesis of MnFe<sub>2</sub>O<sub>4</sub> at Relatively Low Temperatures Materials manganese ferrite mechanosynthesis solid-state synthesis thermodynamic guidelines |
| title | Thermodynamic Guidelines for the Mechanosynthesis or Solid-State Synthesis of MnFe<sub>2</sub>O<sub>4</sub> at Relatively Low Temperatures |
| title_full | Thermodynamic Guidelines for the Mechanosynthesis or Solid-State Synthesis of MnFe<sub>2</sub>O<sub>4</sub> at Relatively Low Temperatures |
| title_fullStr | Thermodynamic Guidelines for the Mechanosynthesis or Solid-State Synthesis of MnFe<sub>2</sub>O<sub>4</sub> at Relatively Low Temperatures |
| title_full_unstemmed | Thermodynamic Guidelines for the Mechanosynthesis or Solid-State Synthesis of MnFe<sub>2</sub>O<sub>4</sub> at Relatively Low Temperatures |
| title_short | Thermodynamic Guidelines for the Mechanosynthesis or Solid-State Synthesis of MnFe<sub>2</sub>O<sub>4</sub> at Relatively Low Temperatures |
| title_sort | thermodynamic guidelines for the mechanosynthesis or solid state synthesis of mnfe sub 2 sub o sub 4 sub at relatively low temperatures |
| topic | manganese ferrite mechanosynthesis solid-state synthesis thermodynamic guidelines |
| url | https://www.mdpi.com/1996-1944/17/2/299 |
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